According to LinkedIn, 87 of the 641 people who say they currently work at Twitter were formerly employed by Google. (Twitter said this week that it has 600 employees, so that number’s a bit off, but probably in the general neighborhood.)

Early Google employees don’t get as much credit as those of, say, PayPal, for founding and funding a new generation of start-ups. But former Googlers seem to have made a practice of infiltrating promising new tech companies as they look for the next big thing.

At one point last year, it was noted that 200 former Googlers worked at Facebook, making up 12.5 percent of its staff at the time, including top executives like Sheryl Sandberg and many of the product people Facebook brought in through acquisitions.

Something similar seems to be happening at Twitter, though it’s still much smaller. CEO Dick Costolo was with Google after it acquired his start-up FeedBurner (but some say that means he’s not truly born-and-bred Google). Co-founders Evan Williams and Biz Stone (both no longer in operational roles) were also formerly at Google, though again, Williams came in through an acquisition (of his Pyra Labs, which made Blogger).

The Google influence seems especially prevalent on Twitter’s product team. Satya Patel, who is director of product management, was formerly a well-respected Googler, and nearly every Twitter product manager seems to have had some history at the Plex — save for the four who were recently let go.

Twitter creative director Doug Bowman came from Google (in fact, he left in a huff), as did general counsel Alex Macgillivray and VP Katie Jacobs Stanton, who leads international strategy.

Glenn Otis Brown, Twitter’s newly added director of business development for media, was formerly products counsel at Google and head of music partnerships at YouTube.

Twitter spokeswoman Carolyn Penner, who herself came to Twitter from Google, said she could not provide any specific numbers about how many of her coworkers matched that description.

A Twitter insider said that Twitter’s Googliness is less apparent than Facebook’s, because fewer members of the core leadership team came from Google. Even if head honcho Costolo did stop through Mountain View en route to hipper San Francisco, execs Jack Dorsey (executive chairman in charge of product), Adam Bain (revenue), Ali Rowghani (CFO) and Michael Abbott (engineering) did not work at Google.

Google isn’t entirely happy to be spawning other people’s workforces. The company has famously paid dearly to keep its top employees from departing to take roles at Facebook, and more recently, Twitter. Twitter and Google have been partners in the past, but more recently have had testy relations over renegotiating a data distribution deal.

Thomas Korte, the ringleader of start-up incubator AngelPad and an early Googler, noted in a recent conversation that following former Googlers’ successful infiltration of Twitter, Square and Foursquare seem likely to be the next ex-Googler targets.

Korte pointed out that Foursquare recently hired the well-connected and respected former Googlers Morgan Missen and Benjy Weinberger (both actually worked at Twitter en route!) and Square recently appointed former Googler Megan Quinn as its director of products.

Besides the beginnings of strong referral networks, Korte added, these up-and-coming companies have one other thing going for them: “They’re the only ones that can cough up the salaries to match Google,” he said.

Jared Cohen (pictured here), who has gained fame as the State Department’s social networking phenom and the youngest member of its policy planning staff, is considering taking a job at Google in a strategic policy role, said sources close to the situation.

Cohen has been in discussions with Google very recently about going there, those sources said, although it is not a done deal.

In other words, the revolving door between Washington, D.C., and Silicon Valley keeps on turning, especially Googlers.

Katie Jacobs Stanton, who worked for both Google (GOOG) and Yahoo (YHOO), recently left a job at the State Department to return to California to head international efforts for Twitter.

Google’s top policy wonk, Andrew McLaughlin, serves as deputy chief technology officer.

Sonal Shah, who worked at Google.org, is now director of the White House’s new Office of Social Innovation and Civic Participation.

And Sumit Agarwal, who was head of Google’s mobile product management, became the deputy assistant secretary of defense for outreach and social media in the Office of the Assistant Secretary of Defense.

Coincidentally, for their Twitter-as-statecraft fame, the 28-year-old Cohen, along with Alec Ross, a senior adviser for innovation at the State Department, got the full New York Times magazine profile treatment earlier this month in a piece titled “Digital Diplomacy.”

Wrote Jesse Lichtenstein:

“Their Twitter posts have become an integral part of a new State Department effort to bring diplomacy into the digital age, by using widely available technologies to reach out to citizens, companies and other nonstate actors. Ross and Cohen’s style of engagement–perhaps best described as a cross between social-networking culture and foreign-policy arcana–reflects the hybrid nature of this approach…They are the public face of a cause with an important-sounding name: 21st-century statecraft.”

If it sounds a lot twee in a policy wonk way, it definitely is, which should fit in well at Google, which could use a few friendlier faces to show off in Washington, where some regulators are eyeballing the search giant’s growing power closely.

In the piece, Cohen is seen as playing the organizer of a private dinner Secretary Hillary Clinton had with some Silicon Valley power players, including Google CEO Eric Schmidt, earlier this year.

He and Ross have also been leading technology delegations abroad to places like Iraq, Haiti, Russia and the Congo, chock full of Internet leaders.

Cohen, who attended Stanford University and was also a Rhodes scholar, was actually appointed by the Bush administration’s secretary of state, Condoleezza Rice.

He is also the author of a book, “Children of Jihad: A Young American’s Travels Among the Youth of the Middle East.”

Google and Cohen both declined to comment.

But to give you an idea of their close relationship, here is a video of Cohen and Ross in a conversation with Schmidt at the the Googleplex in Mountain View, Calif., in March:

It will be like they never left the Googleplex in Silicon Valley if this Washington, D.C., invasion of execs from the search giant keeps up.

The fourth new geek in town is Sumit Agarwal (pictured here), who was head of Google’s mobile product management and has become the deputy assistant secretary of defense for outreach and social media in the Office of the Assistant Secretary of Defense.

Phew! But what’s that? Poking with M-16s? The Berlin Wall? Tweeting troop movements?

In any case, it’s interesting to see so many key appointments in the tech arena going to one company, especially one so immersed now in national and international policy issues.

And especially since Google (GOOG) has begun spending so much money in D.C. on lobbying.

As I reported recently:

According to the most recent public reports filed by Google with the Senate on its lobbying spending there, the search giant has significantly increased its outlay in 2009 from the previous two years.

In 2007, Google spent a total of $1.52 million, which rose to $2.84 million in 2008.

And the 2009 total? Just over $4 million, according to the Lobbying Disclosure Act Database.

That’s probably no surprise given the ever-growing range of issues of concern to U.S. regulators due to Google’s increasing number of deals and because of many new and often controversial initiatives the company is forging forward with.

From pushing for approval of its DoubleClick acquisition in 2007 to its failed attempt to strike a search and online partnership with Yahoo (YHOO) in 2008 to last year’s wrangling with book publishers to 2010’s expected tussle over its $750 million purchase of mobile advertising start-up AdMob, Google’s presence in D.C. is only going to rise as its ambitions expand.

That’s still $2.7 million less than archrival Microsoft (MSFT) spent in 2009, but Google has been gaining on the software giant in a very short time.

In any case, these are former Googlers, who might or might not return to the mother ship at the end of their tenure.

But, for those keeping track, Agarwal will join:

* Former business development and product exec Katie Jacobs Stanton, who was the Obama administration’s director of citizen participation and now works in the State Department.

* Google’s top policy wonk, Andrew McLaughlin, who serves as deputy chief technology officer.

* And Sonal Shah, who worked at Google.org and is now director of the White House’s new Office of Social Innovation and Civic Participation.

Barack Obama has yet to announce who his chief technology officer will be. But he has hired a Silicon Valley exec for another role: Google product manager Katie Jacobs Stanton will be the new President’s “director of citizen participation,” starting in March, sources tell me.

What the job entails isn’t completely clear to me, but I gather that she plans on using Web tools to let, well, citizens participate in the Obama White House.

The model: Google’s “Moderator” tool, which let people submit questions for the Presidential debates, and was later used to let them suggest initiatives for the new administration via its Change.gov site.

No surprise, then, that Google Moderator was one of Stanton’s projects when she worked at Google’s elections group.

Per her LinkedIn bio, she’s also worked on Google Finance and Google’s Open Social initiative. And prior to joining Google (GOOG) in 2003 (which means she came on pre-IPO and is fully vested, if you’re doing the math), she was at Yahoo (YHOO) as a production manager and worked in Yahoo Finance.